I think that they just need to balance it so that you can do whatever you want but there are major incentives to using the right skills with the right class.
I do think that even if jobs don't take away your options of skills to use it will still help with making parties. Because people who want to play as a healer will choose the job for it. If they just make it so that using the wrong job with a skill really makes it lose power then it gives the jobs a good balanced and diversity (becuase me curing while Pug is fine but it should never heal for over 300 hp while I'm Pug). But beyond that I can't understand why if a healer finds a way to get in a few attacks, or a tank keeps a cure handy just in case, and they can still effectively do their jobs, they should have to lose their ability to do anything else.
I guess what I hope happens is that they give jobs diversity but don't take away my ability to experiment and learn what works with what and how to make seemingly odd combos work out for me. I want my characters growth to come form not just level ups but my actual experience and knowledge of the game. My character's level being the entirety of my abilities is getting old.